Famous line in gaming culture, originating in the Star Fox franchise. The line is commonly associated with the character "Peppy", due to his tendency to instruct the player to perform the maneuver, commonly when a scripted ambush or similar event is occurring. Due to his insistence upon suggesting that Fox "Do a barrel roll!" in so many situations, it has come to be parodied as a panacea for all problems.

In the context of the Star Fox franchise: "Fox, it's an ambush! Do a barrel roll!"

In the context of internet communication: "I can't finish the last level of the campaign! Any tips?" "Do a barrel roll."

Comes from Starfox 64. A character would command fox to do a barrel roll in order to prevent being shot to deadness.

A barrel roll is when a fighter pilot makes his ship turn over, very quickly, in mid-air. It makes the wings harder to hit.

It's more common practice to shout this phrase at friends while they play video games. Especially if they can't do anything roll-like. The purpose is to be obnoxious, and quote old video games. Two of most peoples' favorite things.

"Son of a white boy, my Sim will not stop crying!"
"Quick, do a barrel roll!"